This invention relates to drive systems for rotary drums or rolls used, for example, in driving or winding conveyor belts, flexible floors and the like.
A common requirement in the winding or driving of conveyor belts, flexible floors, and the like, is to provide a drive mechanism which is mounted internally of a drum on which the belt or floor is wound. This requirement is particularly relevant where a conveyor or flexible floor is to be used in a confined space which precludes the use of a drum drive mechanism that projects to any appreciable extent from the end of a drum. For example, in trucks having load beds incorporating a driven loading/unloading conveyor, it is desirable for the conveyor (and also its driving drum) to extend substantially across the entire width of a truck body. In this arrangement, it is necessary for the drum drive to be housed internally within the drum, since Federal requirements preclude the use of a drive mechanism which might project from the side of a truck.
Internally mounted rotary drum drive systems are known, such systems commonly comprising a motor and gearbox assembly accommodated within a cavity within the drum. In one known system, for example, the gearbox housing itself is rotated and forms a drive connection to the drum through a mounting flange permanently attached to the internal circumference of the drum, and to which the gearbox housing is secured by a rim-mounting. With this system, however, to allow removal of the gearbox, the drum diameter may need to be larger than would otherwise be necessary. In another known system, the gearbox has an output shaft providing a rotary drive connection with the drum through an internal drum flange. A stationary gearbox housing is mounted on a further flange which is itself attached to a stationary mounting tube. The tube has an internal diameter larger than that of the gearbox and an external diameter smaller than the internal diameter of the drum. This arrangement requires the internal diameter of the drum to be large enough to accommodate the mounting tube and may also require the use of separate drum bearings, since the configuration requires the gearbox output shaft to be a loose fit in the drum drive flange for removal and replacement purposes.